The Danish astronomer Tycho Brahe (1546-1601) carried pretelescopic astronomy to its highest perfection and tried to steer a middle course between the Ptolemaic and the Copernican systems.

Tycho Brahe, referred to by his first name, was born on Dec. 14, 1546, the son of the governor of Helsingborg Castle. His upbringing and education were entrusted to his uncle, Joergen, a vice admiral. When only 13, Tycho began attending classes of rhetoric and philosophy at the University of Copenhagen, but almost immediately he was seized with a frustration which had to do with astronomy. It was the discrepancy between the predicted and observed time of a partial eclipse of the sun. His whole life was to be spent on perfecting astronomical observations and theories to eliminate discrepancies of this kind.

Tycho studied at the universities of Leipzig, Wittenberg, Rostock, Basel, and Augsburg (1562-1570). On his return to Denmark he went to live...